Evaluating the effectiveness of the PolarUs app on quality of life outcomes in people with bipolar disorder: Randomized controlled trial protocol with a qualitative component (Preprint)

BACKGROUND Bipolar disorder (BD) is characterized by recurrent episodes of depression and mania or hypomania. Although BD can be associated with significant disability, mortality, and healthcare costs, people with BD can experience good health and quality of life (QoL). QoL outcomes are a priority for people with BD, and treatment guidelines recommend psychoeducation and self-management support. Despite this, access remains limited, particularly for diverse and equity-denied populations. Digital mental health interventions (DMHIs), including smartphone apps, offer a promising means to improve access to self-management support and QoL monitoring. However, most apps lack BD-specific tailoring, co-design with people with BD, and cultural and linguistic adaptations that support equitable access. The PolarUs mobile app is an evidence-informed DMHI co-designed with people with BD, grounded in the 17 domains of the Quality of Life in Bipolar Disorder (QoL.BD) scale, and supporting self-management through personalized strategies and resources, QoL assessments, and daily mood and sleep tracking. OBJECTIVE This randomized controlled trial with an embedded qualitative component aims to evaluate the efficacy of PolarUs in improving QoL among diverse people with BD in North America. We hypothesize that participants randomized to 12 weeks of PolarUs access (available in English, French, Spanish, and Mandarin Chinese) will show significant improvements in QoL at week 12 compared to an assessment-only waitlist control condition. The qualitative component will explore participants' experiences with and perceptions of PolarUs. METHODS Eligible participants with BD type I, II, cyclothymic disorder, other specified, or unspecified BD residing in North America will be randomized to either: (1) a 12-week period of access to the PolarUs app; or (2) a 12-week assessment-only waitlist period. The primary outcome measure is QoL, measured at week 12 using the Brief QoL.BD scale. Secondary outcomes include self-reported mood and psychological outcomes and exploratory healthcare resource use. Based on previous pilot data, a power analysis (80% power, two-sided α = 0.05) indicated a required sample size of 364, increased to 504 to account for 72% completion, to detect statistical superiority. Semi-structured interviews will be conducted with a purposively selected subsample of intervention group participants (n=30) to explore the acceptability and feasibility of the app, use of self-management strategies, and perceived impact. RESULTS This study was funded by the Canadian Institutes of Health Research in October 2024. Study recruitment is anticipated to launch in November 2026. CONCLUSIONS This study will test PolarUs, the first QoL-focused, BD-specific, and culturally adapted DMHI developed through co-design involving people with BD. Findings will provide evidence on the effect of offering PolarUs compared with delayed access as a low-cost, scalable DMHI for improving QoL in BD. If effective, PolarUs could offer an accessible, scalable tool to enhance self-management and improve outcomes for diverse populations with BD. CLINICALTRIAL The trial has been registered with ClinicalTrials.gov (registration number: NCT07890805).